Oil burner nozzle



Oct. 14, 1952 SCHWlETERT 2,613,737

OIL BURNER NOZZLE Filed Dec. 9, 1950 fmz a ATTORNEYS.

Patented Oct. 14, 1952 v UNITED s-TAT OIL BURNER NOZZLE Gustav Schwietert, McGregor, Iowa Application December 9, 1950, Serial No. 200,027-

More particularly my invention relates to a nozzle adapted for'spraying a mixture of oil and air or other oxygen containing gas into a'combustion chamber such as a boiler-furnace.

" In relatively large furnace installations, large quantities of fuel oil are commonly burned by mixing the fuel oil with air in a chamber exterior to the furnace, and then spraying or ejecting the vapor through an apertured nozzle into the combustion chamber. It is also common practice in such installations to provide an auxiliary supply of air to assistin burning the sprayed oil-air mixture. This can be done by providing a casing about the nozzle adapted to conduct the auxiliary air supply and to release it around the end of the nozzle.

Generally, the nozzles used for spraying fuel oil have consisted of a hollow tube providing a mixing chamber therein, and having a rounded or hemispherical end having a single circumferential raw of apertures. With this type of nozzle a relatively large space is required'to burn the fuel oil. For instance, burnersusing one-hundred gallons per hour of fuel oil are found to require a combustion chamber of at least from ten to twelve feet in length; and, if the furnace cham-' ber is circular in cross section, it will need to be about eight feet in diameter. The required length of the combustion chamber is largely determined by the length of the flame projecting from the end. of the nozzle, and heretofore no effective means has been known'for shortening the length of this flame without sacrificing thoroughness of combustion. Thus oil burning 1.

furnaces have required relatively. large and expensive combustion'chambers.

Another problem has arisen with nozzles of the type described in that the exterior surface of the nozzle surrounding the spray apertures tends to become smoked and carbonized, which frequently progresses to the point of stopping up the apertures. The use of an auxiliary air supply sweeping around and over the apertured surface has proven to be only a partial answer to this problem. This auxiliary air tends to flow in channels or well-defined paths between the apertures and thereby is effective-in removing'the carbon from only a portion of the nozzle surface.

Also, the auxiliary air is only effective. in mixing with the oil around the outside, of the flame, and fails to be mixed with the oil in the central portion of the flame with the result that combustion is less complete.

It is therefore an object of my invention to 4 Claims. (Cl. 15876) provide an oil burner nozzle which allowsla large amount 'of fuel oil to be burned in .a relatively small space. It is 'a further object of myinvention to develop an oil burner nozzle which shortens the length of the flame projected from the nozzle, and thereby allows the combustion chamber to be shortened. Itis another: object of my invention to provide an oil burner'nozzle which causes the auxiliary air to sweep over...the"enti'r.e apertured surface in order to prevent any portion of this surface from becoming carbonized. It 'is a still further object of myinvention to develop a nozzle which will cause lthe' auxiliary air to be thoroughly mixed with all of the sprayed oil to achieve complete combustion of the oil. Further objectsv and advantages will appear as the specification proceeds. In one phase of my invention, I have discovered that the above ob nozzle.

jectscan be substantially accomplished by forming the spray-openings in the hemispherical end portion of an oil burner nozzle in a plurality of arcuate rows which are curved in the same direction and extend generally toward the end of the The details of the apertured arrangement and the new results obtained will herein.-

after be more fully developed.

.My'invention .is shown in an illustrative embodiment in the accompanying drawing, in

which- Figure 1 1s a broken side elevational view of my nozzle; Fig. 2, a top of plan View of the hemispherical spray portion of my nozzle; Fig.3, a

side cross-sectional viewof my nozzle installed within thewall of a furnace and surrounded'by the auxiliary air casing, the nozzle section being taken on line 3-3 of Fig.2; Fig. 4 isa cross.- sectional view of my nozzle taken in section through the annular partition member on-line 4-4 ofFig.3.. a] .1 3.1:. In the illustration given, to designates generally a nozzle adapted for spraying oil mixed with air into a combustion chamber. Nozzle I0 is composed of a hollow tubular. extension H, which has a conicalor, more precisely,ga hemispherical end portion l2. Although I preferto have end portion l2 hemispherical, it will be apparent that it can be modified to approa-cha conical shape. If desiredhemispherical end 12 canbe provided with a flattened head portion l3', and a conical headed button or rivet l4 secured within head l3. As shown in Fig; 3, the conical head sequently beidescribed. .q I have discovered that the operation of n'ozzle cal pattern with respect to the surface of the hemispherical end portion. Basically, I have discovered that spray apertures I5 should be located in rows R around hemispherical end portion I2. I have also discovered that rows R should be curved or arcuate with respect to the surface of end portion l2, and extending generally toward the end of nozzle l0, but inclined away from a direct line to the end of nozzle ill. It is desirable for achieving best results to have rows R similarly curved, and all curved in the same direction. I have also found it desirable to drill apertures l5 perpendicular to the surface of end portion 12, as shown more clearly in Fig. 3.

It will be apparent that the number of holes in rows R as well as the number of rows R will necessarily be varied for nozzles of different diameters. Intheillustration given, a nozzle of about two and one-half inches in diameter is represented. With a nozzleof thissize, as shown, I have found. that excellent results are. obtained 'by using ten; rows of holes having five holes in each-row. 'It-will benoted in the illustrated embo'diment-that asufiicient number of rows is provided so that the rows of holes tend to overlap. This is desirable, as will be described underthe discussion; of the nozzles operation, to cause the auxiliary air'to pass over. the'entire surface of en'd v portion l2.

Asshown.more-clearlyin Fig. 3, the interior of tubular extension I Iisequipped with an annular partition:v member designated generally as It. Parti-tionmember It has annular shoulders I! at it'sforward end which are adapted to snugly engage the interior wall of tubular extensionl I beneath hemispherical portion i2. If desired, shouldersilcan besecured; to tubular extension H, by means of spot: welding or other suitable method such a'sproviding interlocking threads,

Partition member [-5 has a reduced hollow tubular portion '18 which is divided by imperforate partition wall l9. The end of reduced tubular portion l8-is. provided with: threads for. re'ceivingcorrespondingly threaded fuel supply pipe 211.. Adjacent to partition 19 tubular portion I8'-is'provided with openings '20 for admitting. thefueloil to the chan'ibero'r area 21 where it isto be mixed Withthe air, which is brought in through tubular extension I 1' around 'fuel supply pipe- 21 and partition. member [6. It will be underst'oodthat additional openings 211' are located 'circu'mferen tially beneath partition it. Onthelo'tlier side of partition l9: tubular portion [Sis provided'withia series of inclin'edip'assages or openings: 22.. the illustration given, there are two circumferentia'l rowsiof inclined. passages- 2'2;:'containingf six openings each, as seen more clearly inF'igA. It

' will'be readily understood that the number: of

such passages can be considerablyjvaried. The 'inc'lin'ationofpassages '22. toward the end. of "nozzle I 0 is desirable, to impart a swirling motion to the oil: and gascarried'from area 2| 'ton'ozzle mixing chamber 23'.

"As shown in Fig". 3; thenozzle includingithe interior structure previously described, is pref- 4 erably located within a cylindricalcasingi-fl which provides an annular duct -25 aroundthe base of end portion i2. The purpose of'casing 2B is to supply auxiliary air 'tortheflame projected from nozzle 10. Cylindrical casirigfli together with nozzle i0 is: extended "through refractory 4 wall 26 into the combustion chamber (not shown).

' Operation supply pipe 21 is then connected to tubular portion I8.

Fuel oil is supplied, preferably under considerable pressure, through pipe 27. The primary air is supplied through tubular extension H to combine or be mixed with the fuel oil ejected through openings 20 into area 2|; It will be understood that oxygen or other oxygen containing gas can be used in place of air. Also, it will generally be preferable to supply the air to nozzle ill under considerable pressure. The oil and air are'p'artially mixed in space 2| and then forced through inclined passages 22 into the nozzle m'ixin'gchamber 23. The inclination of passages 2'2 ca'us'es the oil and air to-have a swirling motion which-assists in completing the mixing within chamber 23. Also, conical head I ia serves as a baflie member to turn the upwardly projected oil-air mixture downwardly, and thereby improving the dispersion of oil in the air.

The oil-air mixture is sprayed through apertures 15 into the combustion chamber, where. it is ignited by'any suitable means. Once ignited, the flame is continually fed by additional increments of the fuel mixture being continually sprayed from nozzle 10.

The positioning of apertures !5 in a series of rows R which are curved or arcuate with respect to hemispherical end portion [2 causes thefu'elair mixture to be sprayed in fan-like lines of jets. The curving of rows R causes the flame produced by the fan-like jets to be given a sub-- stantia'lly rotary or twisting motion in which layers of the flame fed 'by'th'e fan-like rows of jets combine to produce a turbulent ball of fire.

shown in Fig. 3, I prefer to supply auxiliary air to the flame issuing from nozzle N by means of annular'duct 25.. The inwa-rd curve..- tureo'f casing about duct 25 causes. the auxiliary airto pass, over the surface'of hemispherical end portion I2. The auxiliary air is then enve1-= opedby the twisting fan-like jets of flame, and therebybrought within and disbursed throughout the turbulent flame. This accomplishes a more-effective utilization of the auxiliary airan'd results in better combustion than heretofore obtained.

I The curved inclination -'of rows R deprives the auxiliary air of a low resistance path or *ch'annel, and causes it to sweep over-the entire surface of the hemispherical end portion. Thus, carboni'zation on the hemispherical surfaces or about the apertures is completely prevented, since the air is efifectivein burning oifthecarbon. This eifect'is still more perfectly obtained if' the rows ofopenings are spaced sufiicientl'y =close together to somewhat overlap.

In the actual use of oil burner nozzles having my new aperture configuration, I have found that the space required to burn oil in excess of one-hundred gallons or morelp'er ho'urca'n be about one-eighth that required when: using iro'zzles such as have been hithertoprovi'ded. This is accomplished by producing a turbulent spherical shaped fiame which envelopes and distributes the auxiliary air. Itwill therefore be apparent that my improved oil burner nozzle will lend itself to virtually every size of .industrial heating unit.

Actual operation of my improved oil burner nozzle has demonstrated that substantially complete combustion can be obtained for widely varying amounts of fuel oil supplied to the nozzle. This means that over a considerable range the differing load requirements of a furnace can be met by controlling the amount of fuel oil and air supplied to the nozzle while still obtaining nearly perfect combustion at all settings within the control range. This is a marked advantage over previously known types of nozspirit of my invention.

I claim:

1. An improved oil burner nozzle, comprising a hollow tubular member terminating in a generally hemispherical end portion having apertures therethrough for spraying a mixture of oil and air into a combustion chamber, a partition member secured within said tubular member adapted to provide mixing zones for oil and air, said partition member having a reduced hollow portion adapted to receive a fuel supply pipe, and

a casing surrounding said tubular portion providing a duct opening around the base of said hemispherical portion arranged to direct auxiliary air over the surface of said hemispherical portion, said openings in the hemispherical end portion being arranged in a plurality of rows curved in the same direction and each of said rows having a plurality of openings, said rows extending generally towards the end of said nozzle but being inclined away from the most direct line to the central point on the end of said nozzle.

2. The oil burner nozzle of claim 1 in which said rows are sufficiently numerous to cause the opposite ends of said rows to overlap and in which said openings are perpendicular to the surface of said hemispherical portion.

3. An improved oil burner nozzle, comprising a hollow tubular member terminating in a gen erally hemispherical end portion having apertures therethrough for spraying a mixture of oil and air into a combustion chamber, and a casing sur- 7 rounding said tubular portion providing a duct opening around the base of said hemispherical} portion arranged to direct auxiliary air over the surface of said hemispherical portion, said openings in the hemispherical end portion being arranged in a plurality of rows curved in the same direction and each of said rows havinga plurality of openings, said rows extendin generally towards the end of said nozzle but being inclined away from the most direct line to the central point on the end of said nozzle.

i. An improved oil burner nozzle, comprising a hollow tubular member terminating in a generally hemispherical end portion having apertures therethrough ,for sprayin a mixture of oil and air into a combustion chamber, and a casing surrounding said tubular portion providing a duct opening around the base of said hemispherical;

portion arranged to direct auxiliary air over the surface of said hemispherical portion, said openings in the hemispherical end portion being ar ranged in a plurality of arcuate rows around said hemispherical portion, said rows being similarly curved and extending generally towards the end I of said nozzle and each row containing a plurality of apertures.

GUSTAV SCHWIETERT.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS 

